<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Pdf
 * @subpackage Fonts
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: FontDescriptor.php 18993 2009-11-15 17:09:16Z alexander $
 */


/** Internally used classes */
require_once 'Zend/Pdf/Element/Array.php';
require_once 'Zend/Pdf/Element/Dictionary.php';
require_once 'Zend/Pdf/Element/Name.php';
require_once 'Zend/Pdf/Element/Numeric.php';

/** Zend_Pdf_Font */
require_once 'Zend/Pdf/Font.php';


/**
 * FontDescriptor implementation
 *
 * A font descriptor specifies metrics and other attributes of a simple font or a
 * CIDFont as a whole, as distinct from the metrics of individual glyphs. These font
 * metrics provide information that enables a viewer application to synthesize a
 * substitute font or select a similar font when the font program is unavailable. The
 * font descriptor may also be used to embed the font program in the PDF file.
 *
 * @package    Zend_Pdf
 * @subpackage Fonts
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Pdf_Resource_Font_FontDescriptor
{
	/**
	 * Object constructor
	 * @throws Zend_Pdf_Exception
	 */
	public function __construct()
	{
		require_once 'Zend/Pdf/Exception.php';
		throw new Zend_Pdf_Exception('Zend_Pdf_Resource_Font_FontDescriptor is not intended to be instantiated');
	}

	/**
	 * Object constructor
	 *
	 * The $embeddingOptions parameter allows you to set certain flags related
	 * to font embedding. You may combine options by OR-ing them together. See
	 * the EMBED_ constants defined in {@link Zend_Pdf_Font} for the list of
	 * available options and their descriptions.
	 *
	 * Note that it is not requried that fonts be embedded within the PDF file
	 * to use them. If the recipient of the PDF has the font installed on their
	 * computer, they will see the correct fonts in the document. If they don't,
	 * the PDF viewer will substitute or synthesize a replacement.
	 *
	 *
	 * @param Zend_Pdf_Resource_Font $font Font
	 * @param Zend_Pdf_FileParser_Font_OpenType $fontParser Font parser object containing parsed TrueType file.
	 * @param integer $embeddingOptions Options for font embedding.
	 * @return Zend_Pdf_Element_Dictionary
	 * @throws Zend_Pdf_Exception
	 */
	static public function factory(Zend_Pdf_Resource_Font $font, Zend_Pdf_FileParser_Font_OpenType $fontParser, $embeddingOptions)
	{
		/* The font descriptor object contains the rest of the font metrics and
		 * the information about the embedded font program (if applicible).
		 */
		$fontDescriptor = new Zend_Pdf_Element_Dictionary();

		$fontDescriptor->Type     = new Zend_Pdf_Element_Name('FontDescriptor');
		$fontDescriptor->FontName = new Zend_Pdf_Element_Name($font->getResource()->BaseFont->value);

		/* The font flags value is a bitfield that describes the stylistic
		 * attributes of the font. We will set as many of the bits as can be
		 * determined from the font parser.
		 */
		$flags = 0;
		if ($fontParser->isMonospaced) {    // bit 1: FixedPitch
			$flags |= 1 << 0;
		}
		if ($fontParser->isSerifFont) {    // bit 2: Serif
			$flags |= 1 << 1;
		}
		if (! $fontParser->isAdobeLatinSubset) {    // bit 3: Symbolic
			$flags |= 1 << 2;
		}
		if ($fontParser->isScriptFont) {    // bit 4: Script
			$flags |= 1 << 3;
		}
		if ($fontParser->isAdobeLatinSubset) {    // bit 6: Nonsymbolic
			$flags |= 1 << 5;
		}
		if ($fontParser->isItalic) {    // bit 7: Italic
			$flags |= 1 << 6;
		}
		// bits 17-19: AllCap, SmallCap, ForceBold; not available
		$fontDescriptor->Flags = new Zend_Pdf_Element_Numeric($flags);

		$fontBBox = array(new Zend_Pdf_Element_Numeric($font->toEmSpace($fontParser->xMin)),
		new Zend_Pdf_Element_Numeric($font->toEmSpace($fontParser->yMin)),
		new Zend_Pdf_Element_Numeric($font->toEmSpace($fontParser->xMax)),
		new Zend_Pdf_Element_Numeric($font->toEmSpace($fontParser->yMax)));
		$fontDescriptor->FontBBox     = new Zend_Pdf_Element_Array($fontBBox);

		$fontDescriptor->ItalicAngle  = new Zend_Pdf_Element_Numeric($fontParser->italicAngle);

		$fontDescriptor->Ascent       = new Zend_Pdf_Element_Numeric($font->toEmSpace($fontParser->ascent));
		$fontDescriptor->Descent      = new Zend_Pdf_Element_Numeric($font->toEmSpace($fontParser->descent));

		$fontDescriptor->CapHeight    = new Zend_Pdf_Element_Numeric($fontParser->capitalHeight);
		/**
		 * The vertical stem width is not yet extracted from the OpenType font
		 * file. For now, record zero which is interpreted as 'unknown'.
		 * @todo Calculate value for StemV.
		 */
		$fontDescriptor->StemV        = new Zend_Pdf_Element_Numeric(0);

		$fontDescriptor->MissingWidth = new Zend_Pdf_Element_Numeric($fontParser->glyphWidths[0]);

		/* Set up font embedding. This is where the actual font program itself
		 * is embedded within the PDF document.
		 *
		 * Note that it is not requried that fonts be embedded within the PDF
		 * document to use them. If the recipient of the PDF has the font
		 * installed on their computer, they will see the correct fonts in the
		 * document. If they don't, the PDF viewer will substitute or synthesize
		 * a replacement.
		 *
		 * There are several guidelines for font embedding:
		 *
		 * First, the developer might specifically request not to embed the font.
		 */
		if (!($embeddingOptions & Zend_Pdf_Font::EMBED_DONT_EMBED)) {

			/* Second, the font author may have set copyright bits that prohibit
			 * the font program from being embedded. Yes this is controversial,
			 * but it's the rules:
			 *   http://partners.adobe.com/public/developer/en/acrobat/sdk/FontPolicies.pdf
			 *
			 * To keep the developer in the loop, and to prevent surprising bug
			 * reports of "your PDF doesn't have the right fonts," throw an
			 * exception if the font cannot be embedded.
			 */
			if (! $fontParser->isEmbeddable) {
				/* This exception may be suppressed if the developer decides that
				 * it's not a big deal that the font program can't be embedded.
				 */
				if (!($embeddingOptions & Zend_Pdf_Font::EMBED_SUPPRESS_EMBED_EXCEPTION)) {
					$message = 'This font cannot be embedded in the PDF document. If you would like to use '
					. 'it anyway, you must pass Zend_Pdf_Font::EMBED_SUPPRESS_EMBED_EXCEPTION '
					. 'in the $options parameter of the font constructor.';
					require_once 'Zend/Pdf/Exception.php';
					throw new Zend_Pdf_Exception($message, Zend_Pdf_Exception::FONT_CANT_BE_EMBEDDED);
				}

			} else {
				/* Otherwise, the default behavior is to embed all custom fonts.
				 */
				/* This section will change soon to a stream object data
				 * provider model so that we don't have to keep a copy of the
				 * entire font in memory.
				 *
				 * We also cannot build font subsetting until the data provider
				 * model is in place.
				 */
				$fontFile = $fontParser->getDataSource()->readAllBytes();
				$fontFileObject = $font->getFactory()->newStreamObject($fontFile);
				$fontFileObject->dictionary->Length1 = new Zend_Pdf_Element_Numeric(strlen($fontFile));
				if (!($embeddingOptions & Zend_Pdf_Font::EMBED_DONT_COMPRESS)) {
					/* Compress the font file using Flate. This generally cuts file
					 * sizes by about half!
					 */
					$fontFileObject->dictionary->Filter = new Zend_Pdf_Element_Name('FlateDecode');
				}
				if ($fontParser instanceof Zend_Pdf_FileParser_Font_OpenType_Type1 /* not implemented now */) {
					$fontDescriptor->FontFile  = $fontFileObject;
				} else if ($fontParser instanceof Zend_Pdf_FileParser_Font_OpenType_TrueType) {
					$fontDescriptor->FontFile2 = $fontFileObject;
				} else {
					$fontDescriptor->FontFile3 = $fontFileObject;
				}
			}
		}

		return $fontDescriptor;
	}
}
